com.orchestranetworks.query

Interface Query<T>

public interface Query<T>

An object that represents a compiled and validated SQL query.

A query is executed by calling the method getResult().

Note that this class is not thread-safe.

Since:

6.0.0

See Also:

QueryBuilder

Method Summary

Modifier and Type	Method and Description
String	explain() Returns a meaningful string representation of the query plan that is used to compute the result of this query.
QueryResult<T>	getResult() Executes the query on the registered dataset(s), and returns a result object, ready to iterate.
void	setFetchSize(int rows) Provides a hint to the underlying database with the number of records to fetch at a time from the result of executing this query.
void	setLocale(Locale aLocale) Sets a locale to the query.
void	setParameter(int aPosition, Object aValue) Sets a value to a positional parameter in the query.
void	setSession(Session aSession) Sets the user session on the query.

Method Detail

getResult

QueryResult<T> getResult()
                  throws QueryPermissionException

Executes the query on the registered dataset(s), and returns a result object, ready to iterate.

In terms of isolation, when the result object gets iterated, it is guaranteed that all internal persistence and indexing entities used in this process will utilize the same snapshot (the one at the moment the current method was executed).

Throws:

QueryPermissionException - if a session is provided and at least one forbidden node is used in the request.

explain

String explain()

Returns a meaningful string representation of the query plan that is used to compute the result of this query.

setSession

void setSession(Session aSession)

Sets the user session on the query. This activates the permission checks and sets the session locale.

Applying the permissions checks will have the following effects:

• the records will be filtered using the access rules on records if any;
• a QueryPermissionException will be thrown on execution if at least one forbidden node is used in the query. Currently, this does not take into account record-dependent access rules set on fields.

See Also:

setLocale(Locale)

setLocale

void setLocale(Locale aLocale)

Sets a locale to the query.

See Also:

setSession(Session)

setParameter

void setParameter(int aPosition,
                  Object aValue)

Sets a value to a positional parameter in the query.

A parameter is represented by a question mark ('?') in the query. The first position is 0:

 
   Query<Tuple> query = dataset.createQuery("SELECT * FROM customer WHERE age = ? AND name = ?");
   query.setParameter(0, 42);
   query.setParameter(1, "John");
 
 

The type of the specified value should match the type of the parameter. See Sql Mapping of data types for more information.

See Also:

Request.setXPathParameter(java.lang.String, java.lang.Object)

setFetchSize

void setFetchSize(int rows)

Provides a hint to the underlying database with the number of records to fetch at a time from the result of executing this query. If the fetch size specified is '0', the underlying implementation determines the fetch size independently.

See Setting a fetch size for the limitations when using PostgreSQL as the underlying database.

Parameters:

rows - the number of rows to fetch

See Also:

Request.setFetchSize(int), Statement.setFetchSize(int)